Typically, routers include a motor housing with first and second clam shell halves and a stator which collectively form an internal cavity. The motor assembly includes a rotary armature and a stationary laminate stack. In order to cool the laminate stack and armature in operation, a fan is positioned between the laminate stack and the stator for drawing air across the armature and laminate stack. The fan acts as an axial pump by pumping air axially through the motor housing from a vent on top of the motor housing, along the sides of the laminate stack, and finally through the stator on the bottom, and out of the router. The stator usually includes a plurality of straight fins or vanes to direct the air out of the housing. This configuration usually results in random turbulent air conditions near the router bit as the air passes through the stator.
With this random turbulent air movement, saw dust and debris is not efficiently moved away from the cutting area. Rather, the saw dust and debris covers the chip shield and moves about the cutting area in an undesirable manner. This random movement of chips can obstruct vision of the operator, and adversely affect the quality of the cut.
It is desirable to provide an air flow pattern around the router bit which carries saw dust and debris away from the router in an efficient manner. It is further desirable to avoid random turbulent air conditions near the router bit.